Saw this on another site and thought it was a pretty interesting idea. I'm guessing this isn't a new idea, but it's the first time I've seen it. Rather than an x-pipe or h-pipe, these guys built an x-box.

I wondered why they felt the need to run the forward bars so far forward and then put a 90 degree bent but from the looks of the way they built the stands its up on I would guess they do not have a firm understanding on structural stiffness.

In the interest of saying something positive: I have seen other pictures of this build and the level of detail and quality of work is outstanding. Love the color also.

from the looks of the way they built the stands its up on I would guess they do not have a firm understanding on structural stiffness.

x2. When I saw those stands, I thought oh man, those things could fold like a house of cards. I think I will post something in the build thread. That shop is about ten minutes from where I live.

I'm not sure why they went so far forward with the downtubes either. I want to do some downtubes on my Nova, but with hopes of an improved design per this thread: http://www.offroadfabnet.com/forums/...ead.php?t=8699 Other than the 90 and going so far forward on the frame, how would you change things to make the design better?

x2. When I saw those stands, I thought oh man, those things could fold like a house of cards. I think I will post something in the build thread. That shop is about ten minutes from where I live.

I'm not sure why they went so far forward with the downtubes either. I want to do some downtubes on my Nova, but with hopes of an improved design per this thread: http://www.offroadfabnet.com/forums/...ead.php?t=8699 Other than the 90 and going so far forward on the frame, how would you change things to make the design better?

I just read through the build thread I linked to. Turns out the forward bars on that car do not tie into a cage. I have not set in my mind yet why they are there unless they are just for looks. Maybe someone else is seeing something I am not?

My advice on those bars is similar to the discussion on this board with the panhard bar. Bends are bad. That being said you will probably not be able to get them in a stock chassis w/o a bend. If you can, triangulate from the bend area rearward to stiffen up the bent tube. In addition, realize what you are trying to accomplish with the bar which is to stiffen up the front suspension. Going forward of where the front suspension attaches does not accomplish anything. My $0.02

In addition, realize what you are trying to accomplish with the bar which is to stiffen up the front suspension. Going forward of where the front suspension attaches does not accomplish anything. My $0.02

In the case presented, a 1st gen Camaro receives a similar type of downtube (he calls them "forward struts") without a cage (link to picture), in addition to solid body mounts and subframe connectors. The upgrades are added progressively and the results are below:

Quote:

3820 lb ft/deg Starting Torsional Rigidity
4290 lb ft/deg With Solid Body mounts from Chris Alston (12% improvement for about $100)
4750 lb ft/deg with body mounts and DSE Subframe Connectors (11% additional improvement for about $200; 24% total improvement for about $300).
5305 lb ft/deg with body mounts, subframe connectors, and forward struts (12% additional improvement for about $350; 39% total improvement for about $650 and about 3 days of work).

This would indicate to me that stiffness of the chassis can be significantly increased by this type of downtube. Structure/strength is another topic altogether and I would agree it should tie into a cage.

In my experience with many 1st gen Camaros, the front strut tubes are a must for chassis stiffness even with through the floor welded in subframe connectors. Basically as you probly know, the 1st Gen Camaros front subrame is held on by 6 bolts, well basically 4 because the front two just locate and carry the core support. And of those 4 bolts, they basically bolt through 3 layers of sheet metal attached to a single layer at the firewall. In unmodified form, the factory uses the front fenders and inner wheel wells in a feable attempt to add stability to the front of the subframe which I think they guys in the other thread were trying to compensate for. On a road race, oval or drag chassis, the farthest forward or rearward you need any type of structure is at the shock mount or suspension pick up point farthest to either end. The Y brace coming off the firewall in the other thread looks more for show to me but it is a good idea in any type of performace 1st gen camaro. I would add a removable cross tube as well. from the looks in the other thread, that shop looks like they know what they're doing but I think alot of the car in that thread is just for show and not go.
I'll see if I can get my pics off the old shop computer and post up some photos of a couple of 1st gen cars I've built. One is a SCCA vintage road racer and the other is a TT10.5 stock suspension car. I did a ton of mods to the subframes and cage tie ins to take the wonk out of them.
As far as terminator boxes, I had one on a mustang long ago and I picked up 25hp by putting a true, dimensionally correct x-pipe in it. Look at Dr.Gas or give Burns Stainless a call they can get you the right info on pipe sizes and in/out angles on the X's.

I'll see if I can get my pics off the old shop computer and post up some photos of a couple of 1st gen cars I've built. One is a SCCA vintage road racer and the other is a TT10.5 stock suspension car. I did a ton of mods to the subframes and cage tie ins to take the wonk out of them.

Please do, I'd love to see. I don't plan on anything extreme for my Nova, but I do want to make some improvements.

As far as terminator boxes, I had one on a mustang long ago and I picked up 25hp by putting a true, dimensionally correct x-pipe in it. Look at Dr.Gas or give Burns Stainless a call they can get you the right info on pipe sizes and in/out angles on the X's.

LOL my perspective.
On the SF901
I have never lost power to a dead quiet engine where the same Db reading always showed a dramatic loss X or H. For me that is enough proof of concept, but you have to get the volumes correct.
The X I have seen gains and losses to otherwise separate duals, but most often I've seen ink in the magazines
With a correctly located H, I have always measured a torque boost and I've never seen a loss even if incorrectly located.

Pax

__________________
When did empirical knowledge get replaced by a theoretical education?

On the SF901
I have never lost power to a dead quiet engine where the same Db reading always showed a dramatic loss X or H. For me that is enough proof of concept, but you have to get the volumes correct.

I don't understand what you're saying here. Can you rephrase this? I think what you're saying is the terminator boxes resulted in less noise and more power on the engine dyno than an X-pipe or H-pipe.

This is the exhaust setup on my Nova: 2.5" with 2.5" H-pipe and 2-chamber Flowmasters. I am hoping to adapt it to the new collector locations with the LSx. See any issues? I am not a big fan of the cut & weld on the driver's side instead of a bend. It sounds good though.

I don't understand what you're saying here. Can you rephrase this? I think what you're saying is the terminator boxes resulted in less noise and more power on the engine dyno than an X-pipe or H-pipe.

I am sure I have said something wrong in the following. Oh well, if I state that this is my opinion do not declare a single source and reference nothing other then my direct experience I should be covered. I really have tried to keep this simple I guess I’ll soon know up or down.

So the X pipe… verses the H pipe verses the Termination Box.
For maximum performance both the X and the H are both critical in their volume, shape and location, a fact that is often conveniently ignored for packaging of the typical ‘Off Road’ bolt in H/X pipes thus negating much of the possible benefit beyond placebo. That said I have never seen the balance loose power but I have seen the X do so, the exact reason for that I may never know, but I have my guesses. However the gains in power with such a bolt on system can be significant because even today OE exhaust systems are designed by BeanCounters rather then engineers.
In any internal combustion exhaust system the size location and length of every component must be factored into a systems approach. This consideration must be done for both gas flow and pressure waves and is far more important in the NA and crank driven Supercharged engine then a Turbocharged engine which is far less critical after the turbo, IE to big and to short are darn near imposable. Gas flow is fairly well understood the pipes must be the right diameter and length with all bends and transitions being smooth, at the right rate and in the correct location. A note on the modern car/truck for the vehicles with Cats basically attached to the engine, the first change in volume was the CAT and the greatest restriction to flow is likely the Cat and while you can huff and puff and maybe get an improvement over the existing exhaust system, depending on just how bad it is, the cork remains the Cat. Sound, still does not equal power!

The X and H pipes must be located in the system correctly and must be sized correctly to function. The dynamics of the exhaust both from a Gas flow and a Finite Amplitude Wave function are predictable and by nature these systems must include the full length of the exhaust system. The X pipe is supposed to mix the pulses between the two cylinder banks and it is possible that at some gas speed and some frequency the effect might just work; if all of the upstream tube is correct, AND if the downstream tubing is the correct size & length the rest of the time it is doing nothing and often hurting gas flow in my experience (which may be 100% wrong, yes you can measure 100% wrong with a Dyno).
The H pipe being 90° to the main pipe (ideally) has far less negative effect on gas flow when it is out of sync. The H pipe or balance tube, etc is a simple and cost effective design to execute and as I have said I have never seen a negative result even when not optimally located. In both cases the total length and volume on the full length system must be correct to achieve maximum results.
In both the H and X system such as the ones pictured in this thread the length volume and the geometery have to be dead on to see real gains. The headers must be designed to match the RPM where the maximum effect is desired way generally long tubes and smaller tubes for lower RPM and the opposite for high RPM. The collector is a cut and try deal but again longer will bias to the bottom-end, and then there is the next expansion typically the Cat or Muffler and finally the tail pipe. Every change in volume produces a pressure wave. Get them all timed right make power.
The tuning effect of the X and H (and headers) is RPM static, unless they can change their physical location in the system, and/or their shape, and/or volume. At best the full (peak) tuning benefit lasts a few hundred RPM total. Extremely worth the effort on any track vehicle regardless of type and just as desirable on the street vehicle IF you honestly know where you want it! Get the volumes and lengths right and you get power for about 500-RPM.

The Termination Box is an interesting device because where the H and X pipes still are directly effected by the entire length of the exhaust system and every component in them, the TB in effect causes the exhaust to see the atmosphere at the end of the inlet pipe (collector) at all RPMs thus as long as there is the ability to flow enough to handle the volume of exhaust (CFM) produced, the configuration of the exhaust system downstream from the TB is virtually irrelevant.
Interestingly with the TB the effect is constant when the volume is correct the exhaust always reacts as if it is running only the tubes ahead of the TB and there in lies the difference between the two devices the X and H are trying to make power where the TB is simply retaining the benefit of the development of the set of tubes that make the most power: The Header(s)!
Summery.
Any exhaust system, a tuned full, X, H, or headers will only have its maximum effect over a few hundred RPM band.
The Terminator Box (Helmholtz Resonator) effectively erases the exhaust system behind the TB at all RPMS. Thus it is possible to design a really functional system ahead of the end of the collector with out the requirement of tuning the system behind that point. To put it another way you can build a sweet set of headers and not Muck it up with the rest of the system.
I can on the street run an effective (quiet) muffler that would choke the flow of the exhaust in a conventional system X or H without penalty.
Noise does not equal power.

__________________
When did empirical knowledge get replaced by a theoretical education?

I don't understand what you're saying here. Can you rephrase this? I think what you're saying is the terminator boxes resulted in less noise and more power on the engine dyno than an X-pipe or H-pipe.

This is the exhaust setup on my Nova: 2.5" with 2.5" H-pipe and 2-chamber Flowmasters. I am hoping to adapt it to the new collector locations with the LSx. See any issues? I am not a big fan of the cut & weld on the driver's side instead of a bend. It sounds good though.

More opinion...
Flowmasters... If you read their hype they are the best, most accurate mufflers on the market and they flow more air then a smooth pipe. They can hold 0.004" in the location of their baffles and that is not too shabby Who knows if you need 0.004" accuracy? Is the tube used to attach to that muffler held to 0.004"? Does that make it flow? I can say for myself that in steady state testing on the bench they don't flow near as well as a pipe, and in testing on the Dyno they didn't make the same power as the open pipe. Reach your own conclusions!
So why the hype and apparent success...
...my take is.
DumbF'z are still buying Tornado's, stil looking for SplitFire plugs and still think you need "Back Pressure" to have any engine run correctly...
Back when Mr. F started Flowmaster they were being attached to the end of a racing exhaust system that presumably was close in its configuration to being optimal; so bolting a suitcase to the end of it really had little effect because the volume in the muffler mimicked the open collector! Under 100Db, little loss: Now that is a win!

The problem is Physics and gas laws have not changed so, when applied to say where you have yours is six feet back from the collector: is that where you combination of components wants to see the end of the tube? I sincerely doubt it maybe on the 27th reflection that might be a possible spot!
So now you have a expansion box that is located in the wrong place(likely) and is a flow restriction (likely) on top of that.
I have made FM'z work it really is just a matter of figuring out how to get them to fit much closer to the engine, or, saying that the minimal power lost is a fair price to pay, or, I like the way they sound, and hey that is a-ok to choose!

As hard as I just knocked Flowmaster; I need to say clearly they build a high quality product, I use many of their accessory products here and there and I will install a system just like you have because while not optimal I can be sure that it will not comeback for quality issues in the can!!

Entropy, IT is more then a screen name

PS. IMO: Flowiez sound like S#!t

__________________
When did empirical knowledge get replaced by a theoretical education?

E - I don't know if I can muster the technical reply your posts deserve, but I will say I appreciate all the info. Lots of people want to feel like they bought the best product out there and will pat themselves on the back for all the great superiorities they perceive it to have. Personally I'm okay with the fact that the Flowmasters I bought aren't the best thing for performance. I am also okay with the system not being optimized, though I do wonder how much I've left on the table.

I went with Flowmasters for the sound. It's a loud, intimidating rumble that I've always admired. Many people have complemented me on the exhaust note, but the fact is it's a matter of personal preference. I can see your point of view ("Flowiez sound like S#!t"). When I hear a Harley driving around, it sounds horrible to me like the engine isn't running right, yet it's one of the most popular and beloved sounds in America. Again, a matter of preference.

As I get older, I'm starting to outgrow the insanely loud exhaust on my car. I have thought about trying to go to the extreme opposite - see how quiet I can make it while maintaining or improving on performance. The terminator box, if properly designed/implemented, seems like one means to that end. But as this is what I already have, I will try to hook it back up and make it work.

E - I don't know if I can muster the technical reply your posts deserve, but I will say I appreciate all the info. Lots of people want to feel like they bought the best product out there and will pat themselves on the back for all the great superiorities they perceive it to have. Personally I'm okay with the fact that the Flowmasters I bought aren't the best thing for performance. I am also okay with the system not being optimized, though I do wonder how much I've left on the table.

I went with Flowmasters for the sound. It's a loud, intimidating rumble that I've always admired. Many people have complemented me on the exhaust note, but the fact is it's a matter of personal preference. I can see your point of view ("Flowiez sound like S#!t"). When I hear a Harley driving around, it sounds horrible to me like the engine isn't running right, yet it's one of the most popular and beloved sounds in America. Again, a matter of preference.

As I get older, I'm starting to outgrow the insanely loud exhaust on my car. I have thought about trying to go to the extreme opposite - see how quiet I can make it while maintaining or improving on performance. The terminator box, if properly designed/implemented, seems like one means to that end. But as this is what I already have, I will try to hook it back up and make it work.

There you go as long as you are happy it is good!
As to how much you are leaving on the table the only way to know is to get on a Dyno and cut and try. Worth it? Could be 20 HP, yet most people will leave the 30+HP trapped in the oil pan of the typical SB Chevy... Still it could be 20 hp and quiet

To quiet it down move the Boxes forward and add as much tail pipe as you can.

__________________
When did empirical knowledge get replaced by a theoretical education?

Looking at other information about terminator boxes the blue car above doesn't fit the bill, it just uses a fancy H pipe fabricated out of sheet metal.

E- that is some really interesting reading that you have there and it prompted me to do some further research where I found an enormous amount of information. Seems like there would be some fun experiments there for a person with a dyno.